The Calvinist Church was not dominant in the Polish-Lithuanian Commonwealth, hence it did not receive endowments from monarchs. Ministers, congregation schools and cultural life had to be financed by members of the Church, especially magnates (whose number among the Calvinists was decreasing with time), gentry and burghers. The article discusses the issue of forms, value and circumstances of the legacies that were recorded in the documents of the Lithuanian Brethren synods from 1611-1640. The analysis includes the social status and gender of the legators. The beginning of the period analyzed is marked with the oldest surviving protocols, while its end is the death of Krzysztof Radziwiłł, the main patron of Lithuanian Calvinists. The Calvinist Church in Lithuania was a legal entity, therefore legators could transfer the ownership of the property to the Bretheren, which strengthened their financial position. In spite of that, if patrons of Calvinism converted to Catholicism (which occurred more and more frequently with time), there were problems with keeping the property that had earlier been donated by themselves or by their ancestors. In this situation an important role was played by the actor of the Lithuanian congregations, who represented the Brethren in court and took care of their financial position. One of his duties was to execute legacies, since not all of them were swiftly passed to the Brethren. When the protocol was drawn up only 40% of legacies were in fact in possession of the Brethren; the other 60% had to be executed. The legacies registered in the documents of the provincial synods of the Lithuanian Brethren include money (152) and non-cash legacies (67); the latter category includes founding churches and their endowments, land, buildings, silver, book collections and various immovables. 162 legacies were left by men, 48 by women and 11 were collective. 80% of the legacies came from gentry, while 14% from burghers. There were 7 legacies left by clergymen and 11 collective ones, in which the donors could have been both noblemen and burghers. The total value of cash legacies in the years 1611-1641 was 57 689.5 Polish zloties; the amounts left ranged from 3 to even 4000 zloties. On the average, 5 cash legacies were recorded yearly, the average sum of the legacy being c. 400 zloties (assuming that the average salary of a clergymen was c. 50 zloties per annum, such a legacy could have sufficed for 8 years). Most of such legacies were left by gentry. Not all the legacies were mentioned in the synod documents with a specified sum, which influenced the calculations presented in the article. Still, congregation actors knew the sums, since those appeared in testament copies, in donation or foundation documents, and in congregation or district registers (this last type of source, however, is rarely available with regard to the period in question). The article presents only an outline of issues connected with legacies left to the Calvinist Church by its members in the Grand Duchy of Lithuania. It is necessary to continue research on this topic, taking into account data from other types of sources preserved in the archives of the Lithuanian Brethren, without which it is impossible to determine the financial position of this religious community.